Electrical relay



July 28,1931. L. v. LEWIS 1,315,947

ELECTRICAL RELAY Filed May 14, 1929 2 Sheets-Sheet 1 my. 5' INVENTOR 1.141.: Wis,

H. auray 1931- L. v. LEWIS ,815,947

ELECTRICAL RELAY Filed May 14. 1929 2 Sheets-Shea}; 2

ion

1; 8 flzsalaiion g aL m =3 1}) K2 ?i-=* 2 /6 [GD GD] H Insulation 121?]29 sulazian b I a 12 12 15 25 7 INVEINTOR. Amy. Len/1 s,

, M awn-M Patented July 28, 1931 PATENT OFFICE .UNITED' STATES LLOYD V'. LEWIS, OF EDGEWOOD BOROUGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH 8c SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA ELECTRICAL RELAY Application filed May- 14,

My invention relates to electrical relays,

' and has for an object the provision of a relay of simple, rugged and compact construction which will operate without appreciable wear or change in operating characteristics over a long period of time and for a very large number of operations. A second object is the provision of a quick acting relay in which the inertia of the armature is reduced to a minimum. and in which the tendency of magnetic flux between the back strap and the armature extension to retard the pick-up of the relay is likewise reduced to a minimum. A still further object of my invention is the provision of a relay in which a single design of structure may be. readily adapted to alarge variety of contact combinations by the employment ot' a minimum number ofwariable elements. I

I will describe a few forms of relays embodying my invention. and will then point out the novel features thereof in claims.

In the accom 'ianying drawings, Fig. 1 is a View showing in side elevation one form of relay embodying my invention. Fig. 2 is a top plan view of the relay shown in Fig. 1. Fig. 3 a'top plan view showing a modiii :2 tion of the relay shown in Figs. 1 and 2 and also embodying my invention. Fig. 4 is a side elevation. and Fig. a top view of a further modified form of the relay shown in Figs. 1 and 2 and also embodying my invention. Fig. (3 is a view showing in side elevation a modified form oi contact structure embodying my invention.

Similar reference characters refer to similar parts in each of the views.

Referring first to Figs. 1 and 2, the relay comprises an L-shaped back strap B of magnetizable material, having a short leg 1 and a long leg 2. A magnetizable core 14 is attached to the short leg 1 by a machine screw 15, and this core lies parallel with the long leg 2 and carries the operating winding 0. Pivotally mounted at. the free or forward end of the long leg 2 is an L-shaped armature A. the two legs 3 and 1 of which are substantially equal in length. One leg 3 of this armature coacts with the free end of the core C. the other leg 4 is, in the tie-energized position,

1929. Serial No. 363,047.

substantially parellel with the long leg 2 of the back strap B. As here shown, the leg 1 of the armature A is bifurcated to form two parallel arms 7. The armature is pivotally attached to the back strap by means of a plate H which is fixed to the back strap leg 2 by screws 5 and projects beyond the free end of the leg 2. The projecting portion of the plate H is provided with two oppositely disposed recesses 6, which receive the two arms 7 of the armature A, whereby the armature is hinged to the back strap without trunnions.

A plate 8 of insulating material is attached to the armature arms 7 by eyelets 9, and projects rearwardly from the armature to coact with and to operate the relay contacts.

The contacts are supported by a metal plate 11, which is attached to the long leg 2 of the back strap by screws 22 and which projects rearwardly beyond the bend 10 of the back strap. The plate 11 carries a plurality of superposed blocks 12*, 12*, etc. of insulating material. and as shown in Figs. 1 and 2, there are three banks of such blocks, the blocks of each bank being attached to plate 11 by screws 13. Referring to the bank a movable contact finger 17 is clamped between blocks 12 and 12, 'and the outer or free end of this finger is provided with a downwardly projecting hook 17 which cooperates with the insulating plate 8. A fixed contact finger 18 is clamped between the blocks 12 and 12 and is retained in its normal position by a relatively stiii' metal stop 19, which is also clamped between the same two blocks. These contact fingers are so ad justed that the fixed finger 18 normally presses against the retaining member 19. and so that the movable finger 17 is normally out of engagement with finger l8 and presses on the insulating plate 8 with sufficient force to swing the leg of the armature A away from the free end of the core 14. \Vhen the relay winding C becomes energized, however. armature A is swung in clockwise direction, so that its leg 3 moves into engagement with the core 14 and the plate 8 moves upwardly causing contact finger 17 to move into engagen'ient with finger 18.

As here shown, a terminal strip' 20 is I insulation blocks such as12.

clamped between the two upper blocks 12 and 12 of the stack J, and a similar terminal strip 20 is clamped between the two upper blocks of the stack L. One terminal 21 of the winding C is connected with one end of the strip 20, and the other terminal (not shown) of winding C is connected with one end of the other strip 20. The other end of each strip is adapted to be connected with the circuit in which the winding C is to be interposed.

I am aware that the general construction of the relay thus described is old, but in previous practice the horizontal leg 4 of the armature A has been extended rearwardly under the contacts, and has been provided with an individual insulating stud for the operation of the contacts of each stack. One of the novel features of my present invention is the provision of the single plate 8 of insu lating material attached to the armature and extending rearwardly under the contacts for the operation of these contacts. One advantage of this feature is that the inertia of the armature is greatly reduced, because the iron ortion of the horizontal leg of the armature is shortened. Another advantage is that magnetic flux between the back strap leg 2 and the armature extension 4 tends to retard the pick-up of the relay, and this effect is minimized in a relay embodying my invention. A further advantage is that one design of armature can be readily adapted to operate any desired number or arrangement of contacts by changing the insulating plate 8.

For example, referring to Fig. 3, the relay shown in this view is the same as that shown in Figs. 1 and 2, except that there are five stacks of contacts J, K, L, M and N, all of which are operated by an insulatin plate which is here designated 8, and w ich is wide enough to extend under all of the contacts.

In previous practice it has been customary to use comparatively thin insulations between conzacts, for example, not over gth inch in thickness, and to make the contact springs much longer in comparison with their vertical spacing, with the result that the motion of the contact points is substantially vertical. An important feature of my invention is that the contact springs are spaced vertically th inch or more by thick This increased spacing in combination with comparatively short contact springs, insures that when a contact is closing, each member of the contact has a horizontal component of motion opposite in direction to the other. This results in a rubbing action which, it has been found, keeps the contacts clean over a long period of time and greatly prolongs their life. Another feature is the provision of an offset adjacent the insulation 12 in the stop 19 so that both upper and lower surfaces of this stop and also those of contacts 18 and 17 are readily accessible, thereby permitting the contacts to be accurately adjusted to specified positions and pressures by suitable bending tools.

Referring now to Figs. 4 and 5, the relay shown in these views is the same as that shown in Figs. 1 and 2, except that the contact supporting plate, which is here designated 11 extends a considerably greater distance to the rear of the bend in the back strap, so that the operating hook 17 ct the movable contact finger 17 is a considerably greater distance to the rear of the free end of the back strap leg 2. The insulating plate, which is here designated 8, has been greatly increased in length, so that it coacts with the loop 17. By means of this construction tlieefliciency of the relay is increased, because the vertical leg 3 of the armature A may be closed to the core in the dc-energized position, due to the fact that for the same amount of motion of contact finger 17 the required motion of the armature is reduced and the difference between the pick-up and releasevalues of this relay is consequently reduced, in comparison with the relay of Fig. 1. As shown in Fig. 4, this relay is provided with a back contact 1723, and a front contact 17.'18, but it is understood that any desired arrangement or combination of contacts may be employed.

Referring now to Fig. 6, the contact assembly shown in this view comprises two superposed sets of contacts comprising two front and one back contacts, involving a lower movable finger 17 coacting with a back contact finger 23 and a front'finger 18, and an upper movable contact finger 27 coacting with a front finger 18. The lower movable finger 17 is provided with a hook 17, as in the preceding views, for coacting with the insulated contact operating plate. The outer end, of the upper movable finger 27 is bent downwardly at right angles at 27*, and a small plate 28 of insulating material is attached to the bent end 27 and arranged to engage with the free end of the lower movable finger 17. It follows that the upper tinger 27 is operated by the lower finger 17 but is insulated therefrom.

The height of the insulating plate 28 of finger 27 is such that insulating block 12 beneath this finger is of the same height as block 12 below finger 17. It follows that contact 18 and its stop 19 may be reversed so as to provide a back contact for finger 27 instead of a front contact for finger 17, and the contact assembly will then comprise one front and two back contacts. It also follows that a second insulated finger 27 and contact 18 may be assembled above the finger 27 and contact 18 as shown to provide three front contacts. It is obvious that a large variety of contact assemblies and combinations may thus be built up by the employment of contact 18 emon 3 with the two types of contact fingers 17 and of the contact fin ers and so provides for 27 and that the number of these assemblies transverse slide the contact fingers and may be readily varied by the employment of high contact pressure. base plates 11 and insulating plates 8 of In testimony whereofIaflix my signature. various Widths. LLOYD V. LEWIS. 70

Although I have herein shown and described only two forms of relays embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended 75 claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is: 1. A relay comprising an L-shaped back- 80 strap having a long leg and short leg, a core attached to said short leg and extending parallel to said long leg, a coil on said core, an L-shaped armature pivotally attached to the free end of said long leg so that the first 85 armature leg coacts with the free end of said core and the second armature leg lies subtantially parallel with and outside of the long leg of the backstrap, said second armature leg being short so that it has minimum 99 I inertia and minimum magnetic coaction with said backstrap, a contact supporting plate attached to the long leg of said backstrap and extending rearwardly beyond the bend in the backstrap, contact fingers mounted on said plate adjacent the projecting end thereof, and a plate oflight weight insulating material attached to the second leg of said armature and-extending rearwardly therefrom to 35 coact with said contact fingers, whereby a 100 relatively small movement of the armature causes relatively great movement of the contact fingers and so provides for transverse slide of the contact fingers and high contact 40 pressure.

2. A relay comprising an L-shaped backstrap having a long leg and a short leg, a core attached to said short leg and extending parallel to said long leg, a coil on said core, 45 an L-shaped armature pivotally attached to the free end of said long leg so that the first armature leg coacts With the free end of said core and the second armature leg lies substantially parallel with and outside of the 50 long leg of the backstrap, said second armature leg being short and bifurcated to form parallel arms so that it has minimum inertia and minimum magnetic coaction with said 55 backstrap, a contact supporting plate attached to the long leg of said back-strap and extending rearwardly beyond the bend in the backstrap, contact fingers mounted on said plate adjacent the projecting end there 60 of, and a plate of light weight insulating material attached to the second leg of said armature and extending rearwardly therefrom to coact with said contact fingers,

whereby a relatively small movement of the 65 armature causes relatively great movement 

